Patients with acute leukemia and related disorders will be entered upon the treatment protocols developed by the Acute Leukemia Co- operative Group B. These protocols, used under carefully defined conditions, seek to extend our knowledge as to how best to use both established drugs and new chemotherapeutic agents in the treatment of these diseases. Individuals from this Institution take part in protocol design and evaluation in addition to monitoring the results of treatment on study patients. Patients are also entered into studies which evaluate in a preliminary way, new treatment programs prior to institution of group wide studies. Ancillary investigation concerns the effect of various chemotherapeutic agents in in vitro systems.